Field of the Invention
The field of the invention relates to nanomaterials, in particular, the use of multifunctional nanomaterials in the diagnosis and treatment of diseases, such as cancer.
Background
Advances in materials science have lead to the availability of nanoparticles for use in life science research. Gold is an attractive material for biomedical applications on the basis of its biocompatibility. Bhattacharya et al. Adv Drug Deliv Rev 60(11):1289-306 (2008). Gold nanoparticles have long been a subject of research for their unique optical properties. The collective response of the electrons, known as the plasmon, gives rise to strong optical resonance and large and fast nonlinear optical polarizability. The optical properties are well described by the classical Mie theory and are the subject of much interest for their applications in, for example, optical filters, labeling in microscopy, single-electron transistor and molecular detection via surface enhanced Raman scattering (SERS). See e.g., Bohren et al., Adv Mater 11:223-7 (1999); Csaki et al., Nanotechnology 14:1262-8 (2003); Sato et al., J Vasc Sci Technol B 15(1):45-8 (1997); and Nie et al., Science 275(5303):1102-6 (1997).
In terms of optical properties, the strong plasmon resonance of gold nanoparticles can be tuned by the size and shape of the nanoparticle. For example, the well-known 520 nm plasmon resonance of spherical shape gold nanoparticles shifted only about 25 nm to longer wavelengths as the particle size was increased from 5 to 80 nm. Adopting more complex shapes such as nanorods and nanoshells enables much wider tunability encompassing the visible and infrared region.
Specific sizes and shapes of gold nanoparticles function as near infrared absorbers, to the point of causing tissue destruction by thermal ablation. Hirsch and colleagues were among the first to specifically report the use of nanoparticle mediated thermal ablation for the destruction of tumor tissue. Hirsch et al., Proc Natl Acad Sci USA 100(23):13549-54 (2003). In these early studies, breast cancer cells were exposed to metal nanoshells in vitro. With the application of near infrared light (820 nm, 4 W/cm2), cells linked to the nanoshells in the laser's path were ablated, while this same light had no effect on cells that had not been incubated with the nanoshells.
Additional studies have conjugated nanoparticles with antibodies to target tumor specific markers including HER2/neu24, 25 and EGFR26, 27 in an effort to “target” tumors. Loo et al., Nano Lett 5(4):709-11 (2005); Au et al., ACS Nano 2(8):1645-52 (2008); Patra et al., Cancer Res 68(6):1970-8 (2008); and Huang et al., J Am Chem Soc 128(6):2115-20 (2006). Huang et al. report on gold nanorods conjugated to anti-EGFR antibody that was cultured with both non-malignant (EGFR-negative) cells and malignant (EGFR-positive) oral epithelial cells.
Bladder cancer is a common cancer with an estimated 70,980 new cases and 14,330 deaths predicted in 2009. Most patients present with non-muscle-invasive (superficial) cancer that is initially treated with cystoscopic resection, followed by the possible addition of intravesical therapy which is administered directly into the bladder. Bacillus Calmette-Guerin (BCG), a live attenuated form of Mycobacterium bovis, is the most commonly used intravesical agent and has a proven clinical benefit in treating early-stage bladder cancer. Shelley et al., Cochrane Database Syst Rev 2000(4):CD001986; and Herr et al., J Clin Oncol 13(6):1404-8 (1995). Despite these treatments, many patients with non-invasive bladder cancer have a recurrence, with a recent analysis of several large studies reporting a recurrence rate of 39% after BCG therapy. Kirkali et al., Urology 66(6 Suppl 1):4-34 (2005); and Bohle et al. J Urol 169(1):90-5 (2003). In patients with high risk, non-invasive bladder cancer, recurrence after BCG is very common with a recurrence rate in excess of 50%. Treatment options at recurrence include repeated intravesical BCG with our without interferon, alternative intravesical treatments such as traditional chemotherapy agents (e.g., mitomycin, doxorubicin, etc.), or radical cystectomy (bladder removal). Superficial bladder cancer may also progress to metastatic bladder cancer, which is lethal. Additionally, BCG therapy is associated with notable adverse events. An analysis of six well designed trials with BCG for superficial bladder cancer reported cystitis (67%), hematuria (23%), fever (25%), and increased urinary frequency (71%). Intravesical BCG use can uncommonly cause a systemic infection with associated caseating granulomas in distant organs such as the liver, lung, bones and vascular structures. Such dissemination requires treatment with anti-tuberculosis medication in cases with persistent findings or symptoms. A sepsis syndrome after intravesical BCG is observed rarely, but represents a potentially fatal complication.
Beyond the difficulties of treating superficial disease, the identification of recurrent disease also represents a major clinical challenge. While some tumors are exophytic (physically extending from the bladder mucosa) and easily observed visually, other tumor recurrences are flat and not easily recognized visually. In the past, random blind biopsies have been advocated to identify such lesions, although this approach is not currently deemed effective or sensitive. In addition, fluorescence endoscopy after instillation of a porphyrin (e.g. hexaminolevulinate) has also been attempted in an effort to increase tumor detection. Unfortunately, randomized clinical trials have yielded mixed and conflicting results, with 2 randomized trials failing to show a clinical benefit with the use of fluorescent endoscopy.
Epidermal growth factor receptor (EGFR) may play an important role in bladder cancer pathogenesis, in addition to other cancers. Twenty years ago, Messing and Reznikoff reported that EGF stimulated the growth of urothelial cancer cell lines in a dose-dependent fashion. Messing et al., Cancer Res 47(9):2230-5 (1987). Early pathologic investigations associated diffuse EGFR protein expression in urothelial cancers with increased proliferation as measured by Ki67 staining, suggesting a correlation with EGFR and the proliferation rate of urothelial cancers. Wagner et al., Hum Pathol 26(9):970-8 (1995). Consistent with these findings, transgenic mice with urothelial specific overexpression of EGFR develop significant urothelial hyperplasia. Cheng et al., Cancer Res 62(14):4157-63 (2002). More recent studies of human samples demonstrate that increased EGFR protein expression is observed in bladder cancer as compared to normal urothelium. In one case series, EGFR protein expression was noted in 2 of 15 normal urothelial samples compared with 13 of 19 patients with muscle-invasive, localized bladder cancer. Rotterud et al., BJU Int 95(9):1344-50 (2005). When EGFR protein is observed in normal urothelium, it is commonly in the basal portions, in contrast to its superficial (luminal) or diffuse distribution in most cancerous settings. Messing et al., Cancer Res 50(8):2530-7 (1990).
There is a clear unmet medical need in the treatment and detection of non-invasive bladder cancer. Current detection methods include routine cystoscopy, oftentimes starting at the frequency of every 3 months and with decreasing frequency over time. This is used in conjunction with cytological investigation, looking for shed cancer cells, and oftentimes with fluorescent in situ hybridization (FISH), assessing for genomic changes in the shed cells as another method of detecting an active cancer. The use of these methods and the prolonged courses of retreatment have led to the identification of bladder cancer as one of the most expensive cancers to manage, which has been estimated at >$100,000 lifetime costs. Improved therapy for superficial bladder cancer therefore represents a significant current clinical need.
For these reasons, what are needed are compositions and methods for the improved detection and treatment of cancers, including bladder cancer.